The Lyra family of USB audio interfaces offers Prism Sound performance at its most affordable ever. They are based on the Orpheus audio path and clock circuitry, but in a smaller package for those who don't need eight channels of analogue I/O.

Lyra is based on an ARM Cortex processor design which offers class-compliant USB and the possibility for future Ethernet AVB interfacing, plus DSP and local mixing capacity beyond that of the present Orpheus platform.

Analogue and digital input channels are available as inputs for your audio workstation software through the host computer's audio driver. Similarly, analogue and digital outputs and stereo headphone outputs can be played independently.

For low-latency foldback or monitoring to headphone or main outputs, each output pair (1-2, 3-4, digital out or the headphone output) can optionally be driven from the built-in DSP mixer with an individual local mix of any selection of inputs through the controller applet. All analogue inputs are electronically balanced with automatic unbalanced operation. Analogue outputs are electronically balanced with 'bootstrapping', i.e. level is maintained if one leg is grounded.

Verifile is a radical new proprietary technology exclusive to Prism Sound which allows computer audio streams and recorded files to be quickly checked for a wide range of clicks, errors and dropouts, without any compromise in the audio content or any additional metadata.

Verifile is a solution to the issues of reliability that have plagued critical recording projects ever since the adoption of computer recording of audio. Typically, general purpose computers whether Mac, PC or other OS, are designed to perform a wide range of simultaneous tasks of which audio recording is just one. Even if the user would like audio recording to be given top priority, the computer's operating system is not designed that way, and (even if optimally configured, which they seldom are) it will, now and again, interrupt audio recording to do something else. This is especially true when dealing with many channels of high resolution audio, perhaps with low latency, which needs a continuous high data throughput. The result is usually a recorded 'dropout' of some kind: anyone who has recorded audio on a computer is familiar with repeated or missed samples or entire sections, random clicks, pops - even channel swapping.

Verifile is a ‘fragile steganographic’ process which embeds derivative data within the dither of the ADC, containing a rolling hash code which allows the audio data to be thoroughly and continuously checked. Recovery of this data from the audio stream or file enables verification that the stream or file contains exactly the audio data that was produced by the ADC at the time of recording. Any incorrect samples, missing or repeated audio segments or any other audio errors in the resulting files can be reliably detected, providing complete confidence that the recorded file is error-free.

Processing of any kind of a Verifile recording such as EQ, level changes, additional re-dithering, sample-rate conversion etc will result in a failure to decode the rolling hash code in the dither and hence indicate that the recording is not an original.

Lyra makes no compromises on audio quality. It is the result of years of research and development into digital audio conversion and extensive dialogue with Prism Sound's customers.

The Lyra design brief was: Prism Sound quality at an even more accessible price point. Lyra has the same no-compromise analogue front and back ends as its brother Orpheus, with the same fully-balanced-throughout architecture and the same isolation barriers protecting the analogue from digital and computer interference.

Lyra draws on Prism Sound's years of experience in developing digital audio products, including its range of audio test equipment, adopted by a wide variety of clients across the audio industry from pro-audio to consumer electronics. This experience means that Lyra is well-behaved both as a computer peripheral and an audio processor.

Reliability is vitally important in professional recording. Prism Sound has always made extensive use of precise software calibration techniques in its converters - pots and tweaks are always unreliable, so there are none.

The design team has gone to great lengths to minimise noise and interference, in particular hum. All of the analogue circuits have galvanic isolation, while the unit's electronically balanced I/O allows it to handle common mode interference sources as well as enabling trouble-free connection to unbalanced equipment.

It is often said that THD+N figures do not always correlate well with the perception of sound quality and this is true - partly because the traditional measures of THD+N or SINAD expressed as RMS figures are rather a broad measure. With this in mind, we have taken great care to make sure that not only is the RMS THD+N figure very good, but the Lyra noise and distortion spectrum is beyond reproach and that Lyra provides the most transparent listening experience.